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The effect of intensity of excitation on CdSe/ZnS quantum dots : opportunities in luminescence sensing

Sutter, Jens U. and Birch, David J. S. and Rolinski, Olaf J. (2011) The effect of intensity of excitation on CdSe/ZnS quantum dots : opportunities in luminescence sensing. Applied Physics Letters, 98 (2). -. ISSN 0003-6951

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Abstract

We report changes in the photophysical properties of core-shell type CdSe/ZnS quantum dots (QDs) under optical irradiation. QDs either in aqueous solution or immobilized in a silica sol gel matrix have been excited at different wavelengths and fluxes. Illumination of the sample with 140 fs 700 nm Ti:sapphire laser pulses of the peak power of the order of 4 GW/cm(2) caused gradual increase in the luminescence lifetime from an initial value of 3.5 increasing to 4.5 ns and an increase in luminescence intensity by similar to 8%. Using about 16 GW/cm(2) peak power resulted in a shortening of the luminescence lifetime to 3 ns and a decrease in intensity by similar to 75%. Both photobrightening and photodarkening were fully reversible. We discuss the kinetics of photobrightening and photodarkening and investigate the suitability of QDs as luminescence lifetime sensors with tunable parameters.

Item type: Article
ID code: 30188
Keywords: live cells, in-vivo, nanoparticles, anisotropy, Physics, Physics and Astronomy (miscellaneous)
Subjects: Science > Physics
Department: Faculty of Science > Physics
Related URLs:
Depositing user: Pure Administrator
Date Deposited: 15 Nov 2011 16:48
Last modified: 27 Mar 2014 09:17
URI: http://strathprints.strath.ac.uk/id/eprint/30188

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